1. Field of the Invention
The technology described in this specification relates to a semiconductor module.
2. Description of Related Art
Japanese Patent Application Publication No. 11-045977 (JP 11-045977 A) describes a multichip module that has stacked structure in which an active element substrate having a bare chip part, a passive element substrate having a resistor and a capacitor and the like, and a metal shield plate, are stacked together in this order. With this multichip module, thermal conductivity is greater, using a metal plate than it is using an insulating substrate as the base substrate that forms the active element substrate, so heat is able to be better dissipated from the bare chip part.
Typically, with a semiconductor module provided with a semiconductor element that consumes a large amount of power, cooling the semiconductor element becomes an issue. With the multichip module described in JP 11-045977 A, the semiconductor element is able to be cooled using a metal plate as the base substrate that forms the active element substrate. However, this multichip module is a multi-layered structure in which a plurality of substrates and a shield plate are stacked together, so it is difficult to sufficiently transfer heat in the substrate stacking direction. Thus, heat from a semiconductor element that consumes a large amount of power may not be able to be sufficiently dissipated just by using a metal plate for the base substrate that forms the active element substrate. One way to more appropriately cool a semiconductor element that consumes a large amount of power is to mount a radiator to the substrate. However, many elements including a capacitor and so on are mounted on the substrate, and it is difficult to mount a radiator in addition to these elements due to spatial constraints. Also, even if a radiator were able to be mounted, space for mounting other elements would be limited by the space taken up by the radiator, so the degree of freedom in design would decrease.